Constant volume pump



Dec. 4, 1934. p o so 1,982,770

CONSTANT VOLUME PUMP Filed July 17', 1929 4 Sheets-Sheet 1 Wrm... fwd???1M Dec. 4, 1934. P. L. TOLLISON CONSTANT VOLUME PUMP Filed July 17, 19294 Sheets-Sheet 2 dezzv w m a A 2 mi J 5 2 w A m 4.7 a a .5 4*

1934. P. L. TOLLISON CONSTANT VOLUME PUMP 4 sheets-sheet 3 Filed July17, 1929 I Dec. 4, 1934. p ITOLLISON 1,982,770

CONSTANT VOLUME PUMP Filed July 17, 1929 4 Sheets-Sheet 4 .Zr/ezr Qwrmyr Patented Dec. 4, 1934 UNITED STATES PATENT orrlca 1,982,770CONSTANT VOLUME PUMP Application July 17, 1929, Serial No. 378,823

zOlaims.

This invention relates to the provision of a piston pump with meanswhereby the same volume of liquid will be pumped at every strokeregardless of the level of liquid in the pump or melting pot or of otherdisturbing influences.

The chief object of the invention is to provide simple and effectivemeans for measuring out a certain predetermined volume of liquid beforethe liquid begins to be delivered out of the spout; to provide simplemeans whereby the pump will have a capacity for delivering more liquidthan required and the surplus will spill out at or above the highestliquid level and the port or ports will be closed at that time, thustrapping in the pump exactly the right amount of liquid, no matter whatthe liquid level is and irrespective of any faults in the valve actionor other features of the pump. This invention is not limited to anyparticular type of pump or to the pumping of any particular liquid butit is particularly adapted for pumping molten metal to stereotypecasting machines.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which Figure 1 isa sectional view of a well-known type of pump with a preferredembodiment of this invention applied thereto; I

Fig. 2 is a plan of the same;

Fig. 3 is a view similar to Fig. 1 showing the invention applied toanother type of pump;

Fig. 4 is a horizontal sectional view on the line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 1 showing the application of theinvention to another form of p p;

Fig. 6 is a horizontal sectional view on the line 6-6 of Fig. 5;

Fig. 7 is an elevation of the means for turning and operating the valve;

Fig. 8 is a horizontal sectional view on the line 8-8 of Fig. 5, showingthe valve operating means in plan;

Fig. 9 is a. view similar to Fig. 1 showing another modification;

Fig. 10 is a sectional view on the line 10-10 of Fig. 9, showing thespout in plan, and

Fig. 11 is a sectional view on the line 1111 of Fig. 9, showing thevalve operating means in plan.

In the operation of a piston pump, especially in stereotyping, it isdesirable that the same volume of liquid be pumped in the same length ofstroke regardless of the level of liquid in the pot or pump, erraticvalve action, or other disturbing influences. This invention is based onthe idea of providing for automatically discharging from the pump, whilethe piston is operating, all except a predetermined volume of liquid sothat the same amount will be discharged from the pump on each c\ompleteoperation of the piston.

It very often happens that the liquid level in the pump is notmaintained and in fact it varies with every pumping operation, becausethere is no means for restoring to the pump the exact amount of metalpumped each time the pump operates.

It is customary to provide an adjustment between the pump and its primemover for increasing or decreasing the volume of metal pumped. Thisadjustment, however, is manually operated and requires constantattention from the operator in correcting for the amount of metaldischarged each time and the metal put into the pump to sustain thelevel. By this invention these difilculties are avoided and the pumpingnecessarily discharges the same amount at each operation, no

manner what the level of the liquid may be.

In the first two figures I have shown a pump of well-known constructionfor stereotyping purso poses, with this invention applied to it. Thispump islocated in an open topped melting pot or receptacle 10 andcomprises a cylinder .11 and piston 12. In the cylinder near the bottomare ports 13 through which the cylinder is filled with molten metal fromthe pot. The metal enters and stands in the pump, at the same level asin the pot outside.

The piston is provided with a rod 14 operated from a shaft 15 by an arm16 thereon. This shaft is oscillated in any desired way to raise andlower the piston. Arm 18 provided with abutment 19 opening andcontrolling closure of valve 21 is adjustably secured to arm 16 by bolt17. This allows relative adjustment between arm 18 and arm 16 so thatthe operation of valve 21 may be regulated as desired.

The body of the cylinder 11 is provided with a discharge port 20 at acertain desired level. This port is adapted to be closed by a valve 21having a spring 22 on its stem for normally tending to keep it closed.This stem is guided in an arm 23 and projects up through it into contactwith the bottom of the abutment 19. When the arm 16 comes down, theabutment 19 comes down with it 105 and opens the valve 21 as shown.

By the raising of the arm 16 and piston 12 the first effect is to closethe ports 13 and thus provide a confined body of metal in the cylinderand adjacent parts up to the level of the metal in the 1 0' pot at thatinstant. The further raising of the piston forces the metal up in thedelivery spout and in the measuring tower 26 at the top of which islocated the port 20. As soon as the metal reaches the level of the port20, with the valve 21 open, the surplus metal will flow out through thisport and the passage 27 back into the melting. pot. The parts are soadjusted or designed that the valve 21' will be closed by the'spring 22when the abutment 19 reaches. a certain predetermined level and when theamount of liquid in the cylinder is just suflicient to cause the rest ofthe rise of the piston 12 to force enough metal out the spout 25 to forma complete casting without surplus.

It will be seen that no matter whether the level of the liquid in themelting pot is high or low, so long as there is enough to provide a moldfull of metal in the cylinder 11 above the piston}.

the mold will be just fllled at each complete operation of the pistonand there will be complete uniformity in the castings produced'as far asthe amount of metal is concerned.

When it is desired to operate the pump without discharging metal fromthe spout 25 a by-pass valve 28 is opened and it discharges into themelting pot. The pump can be tested in this way or foreign particles inthe cylinder can be gotten rid of so as to float on the top of themolten metal in the melting pot outside. The above description showscompletely how this invention can be employed in a practical and simpleway to measure the metal or other liquid discharged by the pump and keepthe volume constant for each pumping operation.

There are several other ways in which the invention can be carried outand inFigs. 3 and 4 it is shown as being applied to a type of pumpemploying a hollow cylindrical valve 30 for closing the measuring ports31. This valve is secured to the piston rod and when the piston rises toa certain elevation the valve will close ,the ports and entrap in theinterior the same amount of metal every time it operates. In this-typeof pump the metal is introduced through a port 32 controlled by a floatvalve 33 as is well known in this art.

In Figs. 5, 6, 7 and 8 I have shown the invention as applied to anothertype of pump wherein the measuring ports 35 are closed and opened by apiston valve 36 having slotted ports 37 and operated by an oscillatingor rotary motion. In this case the valve does not rise and fall but ismounted on a stem 38 on the top of which is located a cam 39 which inturn is operated by a reciprocating collar 40 on the: piston rod 14.This collar has a radial projection 41 entering the cam slot 42 in thecam 39 and consequently turning the valve 36 as the piston rises. Thiscan be timed as well as the others and has exactly the same efiect. Ihave shown a stufllng box 43 for the valve stem 38.

In the last sheet of drawings Figs. 9, 10 and 11 is shown a constructionwhich combines the conplished by the use of a hollow cylindrical'valve45 having slots or ports 46 and 58. It is located at the top of ameasuring tower 47 and is connected by a swivel Joint 48 and pivotedlink 49 to the pump arm 16., when the valve is in the position shown,the. top of the measuring tower isopen and ithas come into thatposition'i'n proper time so that the desired amount of metal willoverflow through the port from the parts below, as in the other case, sothat the rest ofthe upward stroke of the piston 12 will just fill themold.

By operating a link 50 connected to an arm 51 on the valve the oblongslot 56 can be turned to register with the top of the tower 47. Then thepump can be tested and all the surplus metal pours out through this portand through the center of the measuring valve and it acts as a by-passvalve. In this way the single valve performs two very importantfunctions. The link 50 is manipulated by the operator in accordance withhis desire to cast or not cast metal in the mold.

The four forms of the invention illustrated indicate the broad nature ofthe invention and its application to several types of pumps. They areall capable of providing the necessary amount of metal and disposing ofthe surplus so that each action of the piston will force enough metalout of the spout to fill themold or enough of any liquid to performwhatever function is desired. At the same time the mechanism is simpleand the operation can beentirely automatic as has been shown.

Although I have illustrated and described only four forms of theinvention, I am aware of the fact that other modifications can be madetherein by any person skilled in the art, without departing from thescope of the invention asexpressed in the claims. Therefore, I do notwish' to be limited in this respect but what I do claim is:-

I. In a pump, the combination with a cylinder, a piston therein, a spoutfor delivering liquid from' the cylinder, an arm for reciprocating thepiston, a measuring well extending up from the cylinder and anoscillatory cylindrical valve constituting means for controlling thedischarge of metal from the top of said measuring well, of means foroperating said arm for raising and lowering the piston and meansoperated by the motion of the piston for reciprocating said valve, tocontrol the quantity of liquid delivered, said valve being man-

